Comte de fontainemoeeatt



LDE FONTAINE MOREAU.

Pressure Gage Patented Aug. 20. 1846.

Witnesses:

N. PEiERS, Photo LIlhogr-lphe UNITED STATES PATENT onnron,

PETER. ARMAND, OF LONDON, ENGLAND.

BAROMETER;

Specification of Letters Patent No. 4,702, dated August 20, 1846.

'To all whom it may concern:

Be it known that I, PETER ARMAND, LE- COMTE DE FONTAINEMOREAU, being asubject of the King of France, but residing now at N o. 1Skinners'Place, Size Lane, in the city of London, in the United Kingdomof Great Britain, have invented a certain new and useful Mode ofConstructing Barometers and other Pneumatic Instruments; and I, the saidPETER ARMAND, LEOOMTE on FoN- T'AINEMOREAU, do hereby declare the natureof the invention and the manner in which the same is to be performed andascertained are fully described and ascertained in and by the followingstatement, reference being had to the drawing thereunto annexed and tothe letters and figures marked thereon, that is to say The new mode ofconstructing barometers and other pneumatic instruments consists moreespecially in the application of thin sheets or diaphragms of metal,glass, indiarubber, or other flexible air-tight substances to certainapparatus employed for measuring the pressure and elasticity of the airand other fluids in such manner as to form a kind of elastic cushion orbuffer susceptible of the slighest variation of the pressure of theatmosphere or fluid with which it is in contact and consequentlyindicating the amount of the same by the greater or less depression ofthe said yielding substances. And the invention cons1sts generally inthe application of the above principle to all those pneumaticinstruments in which any reciprocating motion and oscillation takesplace upon a variation in the pressure or weight of the super-incumbentcolumn of the atmosphere, or in the pressure of the liquid in which itis immersed, or in the elasticity of a gaseous body and whichinstruments are commonly called barometers, manometers, &c.

I will nowproceed to describe the draw-' ing appended hereto, explainingin the course of the description the working action of the apparatuswhich is therein fully =delineated.

Figure l is a diametrical section of the barometer; Fig. 2 being ahorizontal view of'the same with the dial plate M taken ofi in order toshow the arrangement of the sheet B and the cup G. The instrument isconstructed of brass or any other suitable material impervious to air.The lower part 'A A is a hollow box stoutly made, and strengthened byradial brackets X X soldered internally to insure rigidity in A A.

This box is covered in an air-tight manner by a sheet or diaphragm B Bof metal glass, &c., very thin that it may be the more flexible, andalso corrugated circularly so as to enable it to be depressed orelevated to the greatest extent requisite without rupture.

Underneath this diaphragm B B are the flat annular disks E E E made upof seg-' ments or in entire plates which serve as caps to a number ofspiral springs for the purpose of supporting it againstthe atmosphericpressure. The lower ends of these springs six of which C, C, C, C, C, C,may be seen in the drawing, are inserted in the cavities cut for them inthe false bottom, D D D D D. They communicate their pressure to thedisks E E E, which diifuse it equally to all parts of the delicatediaphragm and I would here remark that I do not limit myself to what Ihave said above as tothe number or arrangements of the springs. I canemploy, for example, a single row of them under the spreading lip of thecup Gr, even a single one or even some concentric springs. I do notconfine myself also to the spiral forms, since I can use steel of theplates m in which lodges the bent end of the other plate at.

C is a cross-bit upon which rests the cup G. e is a similar cross-bitupon which rests the spring which last it is well to makeas long as thebox will admit of in order to weaken it the less.

In the center of the thin diaphragm B B around hole is cut and its edgessoldered to the lips of a small capsule or cylindrical cup G whichprojects into the interior of the hollow box A A, sufiicient space beingallowed between G and D to permit it to be depressed to its greatestrequired deflection. In the bottom of. the box A "A, and immediatelyunder the cup G there is a small-aperture Z for the purpose ofexhausting the air from the box A A. v This is accomplished in thefollowing manner. A little solder is spread around thehole and a flatheaded peg inserted therein sufliciently open to permit the passage ofthe air. The diaphragm B B with the springs, c, 0, 0, 0, c, c, iscompressed to its proper position by means of a board and a press, andis then soldered or cemented to the box A A, being retained in its placeby clamps embracing the board and bottom of the instrument, which inthis state is to be placed under an air pump receiver to which has beenpreviously fitted an airtight stuffing box through which passes a smoothrod capable of moving freely therein. The inner extremity of this rodbears a soldering iron which must be heated before commencing toexhaust. This done, all is ready for the operation of the air pump, andwhen the vacuum is obtained, both in the instrument and in the receiver,since they are in communication by the hole Z, the hot iron must bepressed down upon the peg at z and its heat will cause the solder tomelt around the peg, thereby making a complete and permanent joint. Thepeculiar adaptation of this barometer to its intended object, will before I proceed further be clearly seen. The pressure of the atmospherebeing removed from the under surface of the thin diaphragm the weight ofthe atmosphere on the upper surface will slightly depress the diaphragm;but this weight is variable according to the state of the weather,consequently the amount of depression will be greater or less inproportion to its variation. Therefore all that is required to completethe instrument is simply to provide mechanism for accurately measuringthis depression and exhibiting its amount on a dial or other ordinaryscale. The contrivance which I have adopted for this purpose is verysimple. In the beforementioned cup G is placed a small nut H with aninternal screw thread. This nut is suspended upon a kind of universaljoint which will be better understood by areference vto Fig. 2. The nutH as there seen is not directly attached to the cup G, but is balancedand plays freely on two pivots projecting from a ring which again isbalanced on two other pivots at right angles to the former ones andconnecting the whole with the cup G. This arrangement allows for anyaccidental deviation from precision which may occur in fitting togetherthe several parts. A vertical screw K works in the nut H, or rather isWorked by it, for when the cup G is depressed the nut H catches thethread of the spindle K, and causes it to turn around, when the cup G iselevated the spindle naturally turns in the reverse direction. The upperend of the spindle K, passes through the dial plate M and carries'theindex L which exhibits its variations upon a scale graduated in inchesor any other convenient standard. And here I- would again observe that Ido not limit myself to the above arrangement, since I can employ for thesamepurpose a rack and pinion, or achain and pulley, with two bevelwheels, see Fig. 6, in which the rack and pinion may be replaced by achain and pulley or simply by a horizontal pinion 0, worked by a coggedsegment 3) one of the bent arms of which d juts against projecting pointe of the cup G (as shown in Fig. 10). The projecting knob of the arm (Zis made to screw into the said arm (see Fig. 11), so as to besusceptible of being shortened or lengthened, by which contrivance themovement of the index is easily regulated to correspond with thedivisions of the scale.

The influence of heat and cold in expanding and contracting metals wouldhowever disturb the regularity of its action and the faithfulness of itsindications if not corrected by some means. temperature of the thindiaphragm should cause it to rise it would indicate erroneously a lightstate of the atmosphere. This error is counteracted by a regulatingplate 0 made of two strips of different metals, brass and steel forexample, suppose the upper one expanding less than the other, which isfixed at Q, Q, Q, a small space being left If the increase of between itand the dial M. One end of this plate projects as far as the center ofthe diaphragm where a small hole is bored for the spindle K to passthrough. Upon this spindle a collar is fastened immediately under andabut-ting against. the plate 0, which collar in addition is providedwith a coil spring N in order to keep it gently in contact with the saidplate and therefore steady in the nut H. If from expansion by heat thecup G is elevated, the same temperature also acts upon the plate 0which, on account of the unequal expansion of the two metals of which itis composed, would in this case curve upward to a degree proportional tothe heat and equal to the height which the cup G has risen at the samemoment. This would permit the spindle to rise higher instead of beingturned as would be the case if it were held down while the cup rose.effects of cold the mechanism would naturally act in the reverse manner.

The proportion of this compensation may be lessened or increased byslipping the If the apparatus were under the wedge P nearer to orfarther from the vary the pressure by raising and lowering it, noting atthe same time the arcs which the index L describes upon the dial M inconsequence of the said variations. It will be seen that in theapplication of my principle to various useful purposes any elastic andat the same time air-tight diaphragm may be used, and also that it doesnot require any invariable form of apparatus for the successfuloperation of the said principle. In exemplification 'of this, I subjoinsome modifications of the above arrangement. These are shown in Figs. 3,4, 5 and 6. At Fig. 3 in lieu of the corrugated diaphragm B B, I havesubstituted one of copper at, a, in shape like an annular trough piercedwith radial slots as will be observed in the enlarged segment exhibitionat Fig. 4. This annulus is coated with a lamina of caoutchouc and theouter edge is cemented to the box A A, the inner edge being attached tothe cup Gr which with the rest of the mechanism is similar to that ofFig. 1 and for the same purpose.

Fig. 5 represents two plates connected and entirely enveloped by acoating of caoutchouc or other supple material. The cylindrical tube ofcaoutchouc a: a is kept distended by an internal spiral coil of wire CC. The lower plate is fixed to the bot tom of the box A A and the upperone carries the cup G in which is seen a nut c with a slightly conicalscrew thread for the purpose of receiving a tightening screw f whichlast supports the universal joint of the nut B as above described. Theair is exhausted through the india-rubber pipe 0 which is strengthenedby'an internal lead tube coated with wax. When the vacuum is obtainedthe pipe 0 must be pinched and the projecting portion cut off, and theplace finally sealed with caoutchouc. Fig. 6 represents two plates on a,similar to the above, connected by a deeply corrugated tube of metal,glass, or other suitable material. The cup G carries a rack to work intoa pinion above it, which last communicates its motion, by means of twobevel wheels fixed to the dial, to the index L. Or if the axis of thetube mm be placed (as shown in Fig. 7 parallel to the dial the inion maybe fixed upon the axis of the in ex L and the bevel wheels dispensedwith. This mechanism may also be applied to the other modifications ofmy apparatus. If the fiat projections of the tube 112, m, be thin andlarge, I give strength by stamping each of them with radialcorrugations.

In all these forms if the diaphragms be not alone sufficiently strong,springs must be employed either internally or externally between theprojecting portions of the upper and lower plates (as at a a, Fig. 6);or instead of springs the air may be left in the box A A, but in thiscase greater play must be given to the bimetallic regulator in order tocompensate for the great expansion of atmospheric air.

The principle as above exemplified can also be applied to theconstruction of lhanometers for measuring the pressure or elastic forceof gases or steam. An arrangement for this purpose is seen in Fig. 8.

A is a hollow column communicating by its base with the boiler orreservoir of the fluid to be measured. The top of this column is coveredin steam-tight by the cover I) b in the center of which is attached thecorrugated tube 0 a. The bottom X of this tube according as it is moreor less compressed by the steam raises the standard d which abutsagainst the spring e c. This standard is forked as shown in the sideView Fig. 9, and between the two branches is sus pended on an universaljoint a nut H which in raising or falling turns the spindle of the screwK. This spindle carries at the upper extremity a bevel wheel m, which bycommunicating with four other bevel wheels transmits the indicationsthrough their axes n n and indices L L upon the four faces of the box G.I can also employ as a manometer the arrangement represented for thebarometer, with this difference that the springs must be placed betweenthe flexible diaphragm B B, and the dial M, the steam or gas beingintroduced into the interior of the box A A. It is obvious that thearrangement hereinbefore described may be applied to measuring thepressure of liquids at different depths. I

And having now described the several pur oses in which my principle maybe ren ered useful, I repeat that I do not confine myself to the exactdetails herein described, but that I claim as of my invention theapplication of flexible air-tight diaphragms of any materialsufiiciently elastic, and of any form which will produce the aboveresults; that is to say, to measure the pressure offluids, gases, &c.,by the deflect1ons of the said diaphragms.

In witness whereof I, the said PmRRE ARMANI), Ln COMTE DEFoNTAINEMoREAU, have hereunto set my hand and seal..

L. DE FONTAINEMOREAU.

